Poppet valve



May 4 1926.\ 1,583,432

I M. M. WILCOX POPPET VALVE Filed May 31, 1924 Fg.2 X 1 3 4 L Fig.3 if

Patented May 4, i925. I v

UNITED. STATES PATENT OFFICE.

MERRILL MIQWILGOX OF, SAGINA'W, MICHIGAN; A. ELWOOD SNOW ADMINISTRATOROF SAID WILCOX, :oncmsnn.

rorrm VALYE. 4

Application filed Kay 81,

To all whom it may concern:

Be it known that I, MERRILL M. Wmoox, a citizen of the United States,residing at Saginaw, in the county of Saginaw and St-ate'of Michi an,have invented certain new and usefu? Improvements in Poppet Valves; andI do hereby declare the following to be a full, clear, and exactdescription of the invention, such as will enable others skilled in theart to which it appertains to make and use the same. I

This invention relatesto poppet valves I and pertains more particularlyto gas en.-

p to

gine exhaust valves and the like in which the valve head is made of aniron casting and the stem is of rolled metal, the head and stem threadedand screwed together, and additionally fastened by electric welding sothat the surface metal of some of the threads of the head and stem isslightly fused.

Such a valve construction and the meth- 0d of making it are describedand claimed in my Patent No. 1,470,041, issued Oct. 9, 1923, to whichreference may be had.

The objects of my improvement are as follows: first,'to cheapen the costof construction by fabricating the valve stem so as to save asubstantial portion of the valve stem material or bar stock that hasheretofore been required; second, to increase the tensile strength ofthat part of thevalve stem close to the head and within the head withoutthe necessity of a separate manipulation or heat-treat1ng operationtoaccomplish that result; third, to also materially increase theresistance to corrosion of that part of the valve stem near the neck ofthe valve and to do this without the employment of an additional orseparate step in the manufacture of the valve.

My improvement also enables me to produce a valve having a considerablysmaller which my stem diameter at the neck of the valve than heretofore,yet of equal strength, and by reason of this smaller diameter importantstructural advantages are attained that would .othewise not be possiblein awelded head valve of the character referred to and to resentinvention is especially well adapted I \Vith the foregoing and certainother objects in view which will appearlater in the specification, myinvention comprises the the valve partly 1n section.

devices described and claimed and the equivalents thereof.

In the drawings Fig. '1 is a side view of Fig. 2 is a side view of thestem as it appears after the first machining operation.

Fig. 3 is a similar view, showing. the stem after being reduced indiameter at one end and lengthened by swaging.

In the drawings, lie the threaded valve stem which is tightly screwedinto the internally threaded head 2, the stem and head being united byelectric welding, so that the metal of some ofthe threads on the stemand head is fused and welded as described in my above-mentioned 1patent.

I accomplish, t e first of .the objects before enumerated, namely, thesaving of material or rolled bar stock for the valve stems, by the meanswhich will now be described.

The required over-all length L of the valve stem has heretofore beenobtained by cutting the bar stock to that length, but in I myimprovement I cut the stockfor theis customary to use round bar stock ofabout twenty-five sixty-fourths inch diameter and the part 4 is madethirteen sixteenths inch in length. After swaging, the part 4 is reducedto eleven thirty seconds inch diameter and its length is therebyincreased to one and one sixteenth inches, or a net elongation of thepart 4 of Xz -inch. The finished length L is usually six inches andiameter and then by heretofore the bar stock has been initially cut tothat length. Therefore, the method above described elfeets a net savingof one fourth inch, or about four per cent of the entire quantity ofmaterial required for the stem.

In saving this material I also attain a further object of my invention,namely, in-

creasin the strength of the stein where it enters t e neck of the head,and also leaving a sharp-edged shoulder which in practice scrapes thecarbon out of the throat of the valve stem guide. 7

Tests of these stems have shown that the 'swagin 0 eration increases.the tensile strengt 0 the part 4 of the stem at the neck of the valve byapproximately ten per cent.

By the same operation I also attain the further advantage of increasingthe capability of the stem to resist the erosive and corrosive action.of the hot exhaust gases at the place on the stem where they impingemost forcibly during the operation of the engine. This resistance tocorrosion is imparted to the metal by the swaging of the part 4 becausethat operation improves the closeness of the grain of the metal, makingit more 'dense and yet preserving the original 'outer surface or skinwhich is present on rolled bars and which, as is well known, of fersmore resistance to corrosion by hot gases than does a newly machinedsurface.

In Fig. 1 the approximate direction of impact of the hot gases againstthis rolled part of the stem is indicated b the arrow.

Since the swaged stem 5 is not only more resistant to corrosion, but isalso stronger than it was before being swaged, itsthreaded part can beof somewhat smaller diameter for the same strength and thereby I gain astill further advantage which will now be explained. In the welding stepof the method describedv in my Patent No. 1,470,041 above referred to, apart of the metal of the cast iron head 2 is fused in the form of acircular band 6 and the nature of this band is changed by the weldingoperation so that it becomes practically pure white iron and glass-barcapable of resisting a cutting tool or spoiling a drill.

Now, each engine valve is fitted with a pair of drill apertures 7 toreceive a spanner by which the valve is rotated when it is being groundto its seat in the engine. These spanners are of standard dimension andspread and the holes 7 are made accordingly in the valve head after thestem has been welded to the head. Obviously ifthe glass-hard band ofmetal 6 extends too far out into the body of the head it would interfere"with the proper drilling of the holes 7 and it, therefore, becomesofimportance to limit the extent of this hardened area 6 so that itcannot project out to the holes 7. I, therefore, desire to keep thediameter of the art 5 of the stem as small as is commercia ypracticable, in order to keep the outside diameter of the hardened area6 within the required limits.

Since the swaging'of part 5 increases its sion by the hot gases, itenables me also to employ a smaller diameter of would otherwise bepracticab e, keeping within the required limits above mentioned,

tions heretofore required.

The extent of the cost-reduction by reason of the saving of stemmaterial will be apparent when it is remembered that on a productionbasis many thousands of valve stems are manufactured per day and a netsaving of four per cent of the stem material constitutes a real and veryimportant gainb Having thus described my invention, what I claim anddesire to secure by Letters Patent is: p

1. A poppet valve having acast metal head, a wrought metal stem receivedwithin and welded to sai'dhead, said stem initially shorter than itsrequired length when finished, and formed near its end adjacent saidhead with a circular groove, the extremity of said stem swaged tothereby reduce its diameter to approximately the diameter of the bottomof said groove while elongating it to said required finished length andthereby also improving its strength, surface density and capability toresist corrosion.

2. A poppet valve having a cast metal head, a wrought meta-l stemreceived within and welded to said head, said stem being initiallyshorter than its required length when finished, the extremity of saidstem swagd to thereby reduce its diameter, increase its strength andsurface density, and to elongate said stem to said required finishedlength.

3. In a poppet valve having a cast metal head, a wrought metal stem madeinitially shorter than its required length when finished and having anend received within and fixed to said head, the said end swaged tothereby reduce its diameter and to also thereby elongate said stem tosaid required finished length.

' In testimony whereof, I afiix my signature.

' MERRILL M. wrnoox.

art 5 than tensile strength and its resistance to corro-

